Underlay for floor coverings



Dec. 24, 1940. Q. L DALLIA 2,225,906

UNDERLAY FOR FLOOR COVERINGS Filed April 12, 1957 '7 FIG.

WAX F\\ M TOP cEMENTmdus COATING FELT IMPREGNATEDI WITH ASPHALT.

CHEESECLOTH FELT (NOT IMPREGNATED) BOTTOM CEMENTITIbUS com-me BOTTOM COVERED W\TH WAX FHJ'I \NVENTOR LAWRENCE DALLIA ATTORNEY M H. W

Patented Dec. 24, 1940 1 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to an i'in'derlay for floor coverings, such as sheets and tiles of linoleum, cork, wood, rubber, asphaltized materials, etc.

An object of the invention is to provide a relain the floor covering may be cemented.

Another object is to provide an underlay of the character described having a cementitious coating on one or both surfaces to permit of bonding the underlay to the .floor base or floor covering,

or both. And in this connection a further object is to provide a water-activated cementitious coating which is in turn coated so as to permit making, shipping and storing the underlay in rolls without danger of the adjacent roll surfaces becoming stuck together.

A feature of my underlay is that it will stand considerable traffic without injury after being laid and before the floor covering is laid thereon, and may be readily cleaned off. I

Other objects and features will be apparent from the following description, and the .accompanying drawing, in which:

Fig. 1 is a diagram showing a partly broken away perspective view of the underlay; and

Fig. 2 is a schematic representation of apparatus for making the underlay.

The underlay comprises a waterproof top layer 1 of felt impregnated with asphalt, and a water absorptive bottom layer 2 of dry unimpregnated felt. The thickness of each layer is approximately of an inch. The bottom layer is bonded to the top layer by adhesion with the asphalt of the top layer, the asphalt thus being used to saturate the top layerand bond it to the bottom layer.

The felt sheeting used-for each layer may be of the same kind and should have strain-resisting strength and be absorptive to a substantial degree. A preferred felt is of the rag type (commonly known as "deadening felt") and contains a minor proportion of wood fibers (unsized paper, wood meal, wood fiber, etc.) to increase absorptiveness. An example of a suitable felt'of this kind is one composed of approximately 75% rags,

25% paper, 5% wood fiber, and weighs about one pound per square yard, the thickness being approximately inch. This felt sheeting after being saturated with asphalt weighs about 1.4 pounds per square yard.

65 There is interposed, between the top and bot- (Cl. 15-L-49) tom felt layers, a breaker sheet 3 of cheesecloth, i. e'., a thin, loose woven cotton cloth. The breaker sheet does not prevent adequate bonding together of the top and bottom felt layers, since the asphalt will penetrate down through the *5 cheesecloth and unite with the top surface of the lower felt layer. However, the cheesecloth will be more firmly bonded to the upper than the lower felt layer. In the event of removing floor covering cemented to the underlay, the underlay l0 being cemented to the door base, the breaker sheet will facilitate such removal. The underlay will divide, the upper layer and cheesecloth peeling from the lower layer. The breaker sheet is also desirable because of the additional strength 15 which it imparts to the underlay. Moreover, the breaker strip serves as a protection against cutting through the underlay when trimming seams,

and-in special cutting of custom flooring; the softness and drag on the cutting tool informing the operator that the cut is too deep. Furthermore, the breaker sheet'serves as a barrier which prevents shearing or splitting of the lower layer (resulting from contraction of the floor base) from causing shearing of the top layer and, in addition, the lower layer is strengthened.

The lower surface of the underlay, that is, the lower. surface of the bottom junimpregnated felt layer, is preferably provided with a suitable nontacky cementitious coating 4, such as a water- 3 activated paste, of whichmany are known and readily available, as for example the lignin type. This paste coating may be covered with a film of wax 5 deposited'from a water emulsion, which in turn may be dusted over with a commercial grade of talcum. The wax film will serve to protect the paste coating against absorption of atmospheric moisture, and prevent sticking together of adjacent turns when the underlay is made up into rolls and exposed to humid weather 40 conditions. The water emulsion wax coating will decompose and permit activation of the underlying paste when water, is applied at the time of laying the underlay. Dusting will only be necessary when rolls of the underlay are likely to be exposed to very moist conditrons- In the same way, the top surface of the underlay, that is, the top surface of the top asphaltsaturated felt layer, may be provided with a similar cementitious coating 8 protected by a fllm Q of water emulsion wax 1, which'may be dusted over with talcum.

The use of cementitious coatings renders unnecessary the application of cementing material during installation, and has the further advantage that the coating can readily be made of uni-' form thickness and of such thickness as to secure best results. An underlay provided with a. ce-

. mentitious coating on both surfaces will therefore constitute a unitary article of commerce which provides an underlay for flooring and the means for securing the underlay tothe floor base and the floorcovering to the underlay.

Fig. 2 shows in schematic fashion an illustrative method and apparatus for making or assembling an underlay in accordance with my invention. A continuous felt sheet 9 of suitable width to form the upper layer of the underlay is drawn from roll ill; the corresponding lower felt 2 is drawn in a continuous sheet from roll H; and the intermediate cheesecloth breaker sheet '3 is drawn from roll l2. The supply rolls are arranged so that these materials may be drawn therefrom and brought together in the correct sequence.

Felt sheet 9 is drawn through and between guide rolls i3 and I4 located above and at one side of impregnating tank I5 which contains asphalt emulsion bath l6, thence down'into' the asphalt and around guide roll [1, thence up and over guide roll l8 located in the upper part of the asphalt bath, thence down and around guide roll l9, and thence up to and between guide rolls 26 and 2!, which are located above the bath and on the opposite side from rolls l3 and M.

The asphalt saturated felt is n0w ready for assembling as upper layer I of the underlay and is drawn between calendar rolls 22 and 23. At the same time the lower felt 2 is drawn between these rolls in alignment with saturated felt l; and the cheesecloth breaker strip 3 is drawn in interposed and aligned relation between the rolls. The cheese cloth may be given a top coating of asphalt emulsion before passing to calendar rolls 22 and 23, as by being first drawn under and against roll 8 which comes in contact with the asphalt emulsion in tank l5. The three sheetings are thus assembled and united together in the desired relation, to form the underlay, in passing between calendar rolls 22 and.23.

The resultant underlay unit is then drawn between guide rolls 24 and 25 and thence into and through chamber 26. The underlay passes downwardly in the chamber and under roll 21, located near the bottom, thence upwardly between this roll 21 and mating roll 28, the two rolls exerting pressure on the underlay, and thence over roll 28 and horizontally under guide roll 29 and leaves the chamber by passing between calendar rolls 30 and 3|.

Before passing between rolls 2! and 28, the underlay is coated with paste which is sprayed onto both sides through upper and lower spray pipes 32 and 33, supplied from paste vessels 34 and 35. The upper and underneath paste coatings are smoothed out and made uniform when the underlay passes between rolls'2'l and 28, following which the paste coatings may be dried with hot air supplied through upper and lower air pipes 36 and 31 leading from air heaters 38 and 39.

In passing from guide roll 29 to calendar rolls 30 and 3|, the paste coating on the top felt layer of the underlay is sprayed with a wax emulsion to'impart a'protective film, the wax emulsion being supplied through spray pipes, of which pipe 40 is illustrative, fed from wax tank. The

underneath paste coating (on the bottom felt layer) is similarly and simultaneously sprayed with wax emulsion supplied through spray pipes, of which pipe 42 is illustrative, fed from wax tank 43.

After passing between calendar rolls 30 and 3|, the underlay may be dusted on both sides, if desired, with a commercial grade of talcum powder, supplied through pipes 44 and 45 from vessels 46 and 47..

The underlay sheeting may then be trimmed and wound into rolls.

The method of installation is as follows: The floor base is broom cleaned and freed from any grease, oil or wax that may be present. The underlay sheeting is then laid in position coverin the floor base, bulges and contact with walls being avoided, and smoothed out so that it finds its. own level, i. e., is in smooth continuous contact with the floor base. After full coverage has been effected, the sheets of underlay are rolled or folded back without creasing. The entire exposed fioor area is then sprayed with a thin water film, assuming that an underlay is used having an underneath coating of water-activated paste, or is coated with a suitable paste, as the case may be, and the underlay sheeting is then returned to its original position. Any spacings present are filled in. The underlay may be rolled with the usual rolling tools.

Assuming, for example, that linoleum or other sheet floor covering is to be installed, this flooring material is similarly placed in position over the underlay and is then rolled or folded back without creasing. The exposed underlay is then sprayed with water, if it has a top coating of water-activated paste; or if not supplied with a cementitious coating the cement is brushed on at this time; and the fioor covering is replaced in position, and final fitting and trimming operations completed. The floor covering may of course be rolled if desired.

The bottom felt layer of the underlay not being impregnated with asphalt, but being dry and absorptive, makes possible the use of sufficient cement to secure firm anchorage to the floor base without causing unevennesses in the underlay, and

facilitates drying out of the cement after laying the underlay. The top felt layer, being saturated with asphalt and therefore substantially nonabsorptive and impervious to top moisture, will require little adhesive and a thin coating will suffice becauseof this and the flat boundary between the underlay and the fioor covering placed thereon. Thus the possibility of cement or paste crystallization is avoided and a flat surface for the floor covering is readily provided.

What I claim is as follows:

A relatively flexible resilient underlay for floor coverings comprising a waterproof top layer of felt saturated with asphalt, a water absorptive bottom layer of dry unimpregna-ted felt bonded thereto, each of said layers being about 6 inch thick and the felts being of the ragtype and containing a minor proportion of wood fibre, an interposed breaker sheet of cheesecloth bonded to each of said layers by means of asphalt, a nontacky coating of water-activatable paste covering the outer surface of at least one of 'said layers, and over said paste coating a protective film of wax deposited from a water emulsion.

O. LAWRENCE DALLIA. 

